Selection of US-standard cryogenic tubes
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This post was last edited by latern on 2017-12-8 11:33. When the design temperature is ≤-20°C, GB heat exchange tubes are generally used: Q345D/Q345E； SA-334 series low-temperature tubes are specified in ASME Standard II-A; the question is whether SA-179 can be used? For your reference: No explicit rule prohibiting its use was found in the standards ； During software calculation, SA-179 can be used at -46 as long as it is normalized℃ ； The phosphorus and sulfur contents of SA-334 are lower than those of SA-179; only SA-334 contains nickel (around 2-2.6%), while the contents of the other materials are similar. GB6479 Q345E (MDMT-40℃) has a nickel content of ≤0.5%. In practice, SA-334 is difficult to obtain, especially in quantities of 1-2 tons, as suppliers ignore such requests.
Hasn’t anyone among you encountered this at work? I’m seeking advice; for such issues, either solid theoretical backing or successful practical experience is required – otherwise it **affects safety and costs**~~
SA-179 is used at temperatures above -29 degrees, while SA-334 Gr.1 is used at temperatures above -46 degrees. When selecting materials, it is necessary to specify the temperature setting clearly.